The present invention relates to a display unit and a method of manufacturing the display unit; and, particularly relates to a display unit preferable for an upper surface light-emitting type in which display light is picked up from the side of an opposed substrate opposite to a support substrate provided with a display region and a method of manufacturing the same.
The organic electroluminescence (hereinafter referred to as EL) device, which is a self-light-emitting type device (hereinafter referred to as light-emitting device), has a structure in which an organic film that includes an organic light-emitting layer is sandwiched between a lower electrode and an upper electrode, which constitute a cathode or an anode, and is paid attention to as a light-emitting device capable of high-luminance light emission by driving with a low-voltage direct current.
In an active matrix type display unit using such light-emitting devices (namely, an organic EL display) a thin-film transistor is provided at each pixel, and the light-emitting devices are formed at pixel portions on an inter-layer insulation film provided to cover the thin-film transistors. Here, in order to secure an opening factor of the light-emitting devices in the active matrix type display unit, it is effective to adopt the so-called upper surface light pick-up structure (hereinafter referred to as upper surface light-emitting type) in which the light emitted from the light-emitting devices is picked up from the side of the upper electrodes opposite to the substrate.
In such an upper surface light-emitting-type display unit, the upper electrodes are formed of a transparent material, and since such a material has a high resistance, a voltage gradient is generated in the upper electrodes and a voltage drop is liable to occur. Therefore, auxiliary electrodes are provided in the state of being connected to the upper electrodes at spaces between the pixels where the light-emitting devices are formed, whereby lowering of the light-emitting intensity is suppressed.
Besides, it is known that the function of the light-emitting devices may be spoiled due to damage to the organic film by moisture or oxygen. Therefore, in the upper surface light-emitting-type display unit comprising such light-emitting devices, as, for example, shown in FIG. 4, a sealing resin 105 is applied to cover the light-emitting devices 103 provided on a support substrate 101, and a transparent substrate 107 is adhered onto the support substrate 101 through the sealing resin 105, whereby the light-emitting devices 103 are sealed.
However, in the display unit having the above-mentioned constitution, as shown in FIG. 4, inter-device wiring 104 constituted, for example, of the auxiliary electrodes provided in connection with the upper electrodes (not shown) of the light-emitting devices 101 and the wiring for the lower electrodes constituting the light-emitting devices 101 and the like can be seen from the display surface side through the upper electrodes constituting the light-emitting devices 101 and the transparent substrate 107. Here, ordinarily, the auxiliary electrodes are formed of a low-resistance material, such as aluminum, and the lower electrodes of the upper surface light-emitting type display devices 103 are in some cases formed of a metallic material having a high reflectance. Therefore, reflectance for external light at the surfaces of the inter-device wiring 104 constituted of these electrodes is high, and the light h incident from the side of the transparent substrate 107 is reflected by the inter-device wiring 104, causing a lowering in the contrast of the display unit.
Accordingly, it is an object of the present invention to provide an upper surface light-emitting-type display unit having good contrast and a method of manufacturing a display unit suitable for producing the display unit.
In order to attain the above object, according to one aspect of the present invention, there is provided a display unit comprising a support substrate provided with light-emitting devices, a transparent opposed substrate provided with a black matrix and disposed on the side of the surface forming the light-emitting device of the support substrate, and a sealing adhesive resin charged between the support substrate and the opposed substrate in the condition of sealing the light-emitting devices.
In such a display unit, the spaces between the light-emitting devices provided on the support substrate are covered with the black matrix provided on the transparent opposed substrate. Therefore, external light incident from the side of the transparent opposed substrate for sealing the light-emitting devices is prevented from reaching the spaces between the light-emitting devices, reflection of the external light at the surfaces of inter-device wirings can be prevented, and only the light emitted from the light-emitting devices is picked up from the side of the opposed substrate by being transmitted through the adhesive resin and the opposed substrate. Therefore, it is possible to enhance the contrast of the upper surface light-emitting-type display unit in which the light emitted from the light-emitting devices is picked up from the side opposite to the support substrate.
According to another aspect of the present invention, there is provided a method of manufacturing a display unit which comprises the steps of providing light-emitting devices on a support substrate, providing a black matrix on a transparent opposed substrate, and adhering the support substrate and the opposed substrate in the condition where the display devices are sealed with an adhesive resin and the adhesive resin is charged between the support substrate and the opposed substrate.
According to such a method, the black matrix is provided on the side of the transparent opposed substrate provided for sealing the light-emitting devices together with the adhesive resin. Therefore, in the display unit having a constitution in which the light generated in the light-emitting devices is picked up from the side of the transparent opposed substrate, a display unit comprising the black matrix on the upper side of the support substrate provided with the light-emitting devices, as viewed from the display surface side, is obtained. Namely, a display unit in which the black matrix is provided on the side of the opposed substrate capable of picking up the light generated in the light-emitting devices is obtained.
According to a further aspect of the present invention, there is provided a method of manufacturing a display unit comprising the steps of disposing an opposed substrate on the side of a display region provided on a support substrate, adhering the support substrate and the opposed substrate through an adhesive resin, wherein alignment of the support substrate and the opposed substrate is conducted in the condition where the support substrate and the opposed substrate are adhered through the adhesive resin and before the adhesive resin is cured, and thereafter curing the adhesive resin.
In such a method, the curing of the adhesive resin is conducted in the condition where the support substrate and the opposed substrate are maintained in the positional relationship determined by the alignment. In the case of adhering the support substrate and the opposed substrate after alignment, variations in the relative positions of the support substrate and the opposed substrate generated in an adhering operation cannot be corrected. On the contrary, according to the method of the present invention, alignment is conducted after adhesion, so that variations in the relative positions of the support substrate and the opposed substrate generated in an adhering operation can be corrected by the alignment after the adhering operation, and the positional relationship between the support substrate and the opposed substrate is maintained with high accuracy at the time of curing the adhesive resin. Therefore, it is possible to highly accurately position the display devices on the support substrate and the black matrix on the opposed substrate and to obtain a display unit with high contrast in which reflection of external light at inter-device wirings is securely prevented by the black matrix.